How did a former Iowa police officer help persuade one of the world's largest electronics firms to sever ties with America's presidential debates?

It took only a few emails, according to Rick Stewart, who successfully lobbied Philips North America to drop its support of the Commission on Presidential Debates as part of a campaign to open the debates to third-party candidates.

Philips, which was supposed to be one of 10 corporate sponsors of Wednesday night's debate, cut ties with the commission Saturday, citing concerns about appearing partisan. The move came just days after two other sponsors - the YWCA and Bartle Bogle Hegarty, a New York advertising firm - bailed for similar reasons after receiving emails from Stewart.

Now, with three debates left on the schedule, Stewart and a band of anti-establishment activists are training their sights on three other sponsors - Southwest Airlines Co., Anheuser-Busch Companies Inc. and the International Bottled Water Association.

If enough high-profile companies abandon the commission, the activists hope it will change its criteria for candidate participation and abolish the 20-plus-page contracts detailing strict guidelines for the debates.

The commission website says participation in the debates is limited to those candidates who have the support of at least 15 percent of the national electorate according to five selected national public polls. That has been one Republican and one Democrat every year since 1992.

As candidates at all levels hype their anti-establishment bona fides, the commission, a nonprofit organization charged with staging the presidential debates, is under fire from left and right for perpetuating a two-party system.

"It's very concerning to me because [these companies] have done this out of the belief that these are important and valuable events," Janet Brown, executive director of the commission, said in an interview Wednesday. "They are being targeted by people who have an issue with the CPD, and I am very sorry."

Stewart, who describes himself as a libertarian-leaning "nonjoiner," started a group called Help the Commission this summer before taking his case directly to the commission's Washington, D.C., headquarters in August.

"I knocked on the door of [the CPD] office, and the person who answered it peeked out like an Iowa widow in a farmhouse at midnight," Stewart said. Four days and several visits later, a CPD official threatened to have him arrested, he said. "I returned to Iowa. As I worked from here, I realized the CPD was not worth attacking anymore, so I went after the sponsors."

Southwest, Anheuser-Busch and the bottled water industry group said in statements to Roll Call that they would maintain their sponsorships.

"This is a marathon, not a short-term sprint; I've been doing this long enough to know this is a hard nut to crack," said George Farah, executive director of a like-minded organization, Open Debates. "This time, maybe we are tapping into an additional reservoir of anger."

Open Debates was founded in 2003 with the support of prominent voices from across the political spectrum, such as social conservative Paul Weyrich, a co-founder of the Heritage Foundation, and Larry Noble, who served as general counsel at the Federal Election Commission and is now with the Washington law firm Skadden, Arps, Slate, Meagher & Flom.

Libertarian Party nominee Gary Johnson sued the commission and the Republican and Democratic parties last month, alleging antitrust violations and requesting debate access. Johnson and the Green Party's Jill Stein are on ballots in enough states to theoretically win the election. Stein and her supporters held a series of protests Wednesday in Denver, the site of this cycle's first presidential debate.

A contract signed by presidential candidates President George W. Bush and Sen. John Kerry in 2004 limited the number of debates, required audience questions to be preapproved, prohibited follow-up questions and dictated camera positioning.

"The commission allows the major-party candidates to manipulate the process behind closed doors without ever having to play a price politically," said Farah, an antitrust attorney at Cohen Milstein Sellers & Toll in New York City, who funds the effort himself.

But Brown denied that the commission was "party" to any such contract.

"There's never been a contract between the commission and the candidates. Not ever, not now," she said.

The nonprofit raises millions of dollars every cycle to fund the presidential and vice presidential debates. But at least three of the listed corporate sponsors - Philips, Bartle Bogle Hegarty and the bottled-water association - made no monetary contribution this cycle, according to company emails and Brown.

Collectively, the 10 sponsors contributed about $200,000 to support voter education activities this cycle, she said. The rest of the money came from the universities hosting the presidential and vice presidential debates: the University of Denver, Centre College in Danville, Ky., Hofstra University in Hempstead, N.Y., and Lynn University in Boca Raton, Fla.

The commission appears to do the bulk of its fundraising the year before a presidential election, according to recent IRS filings. In 2007, the commission received $5.8 million in contributions. The next year, it raised an additional $1 million and reported spending just more than $3 million on its core mission to "produce, finance, and publicize the general election debates."

Other debate sponsors include the Kovler Fund, the Howard G. Buffett Foundation, Sheldon S. Cohen and Crowell & Moring, a Washington law firm that lobbies on behalf of Novartis, SC Johnson, Pacific Rim Mining and the American Fuel & Petroleum Manufacturers.